Flexible coupling for geared turbine engine

• US 9,863,326 B2
• Filed: 02/18/2014
• Issued: 01/09/2018
• Est. Priority Date: 03/12/2013
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Sheridan, William G., Otto, John R.
• Primary Examiner(s): Laurenzi, Mark
• Assistant Examiner(s): Mian, Shafiq
• Application Number:
  US14/766,766
• Publication Number:
  US 20150377143A1
• Time in Patent Office: 1,421 Days
• Field of Search: None
• CPC Class Codes: F02C 7/06 Arrangements of bearings bearings F16C; Lubricating of turbo machines F01D25/18; of machines or engines in general F01M
• CPC Class Codes: F02C 7/20 Mounting or supporting of plant; Accommodating heat expansion or creep
• CPC Class Codes: F02C 7/36 Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user F02C3/107 - F02C3/13 and F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H
• CPC Class Codes: F05D 2260/403 through the shape of the drive components
• CPC Class Codes: F05D 2260/40311 of the epicyclical, planetary or differential type
• CPC Class Codes: F05D 2260/96 Preventing, counteracting or reducing vibration or noise

Abstract

A gas turbine engine includes a fan shaft arranged along an engine central axis, a frame supporting the fan shaft, a gear system rotatably coupled with the fan shaft, and a flexible coupling at least partially supporting the gear system. The flexible coupling defines, with respect to the engine central axis, a torsional stiffness TS and a lateral stiffness LS such that a ratio of TS/LS is greater than or equal to about 2.0 to reduce loads on the gear system from misalignment of the gear system with respect to the engine central axis.

Claims

1. A gas turbine engine comprising:

a fan shaft arranged along an engine central axis;

a frame supporting the fan shaft;

a gear system rotatably coupled with the fan shaft; and

a flexible coupling at least partially supporting the gear system, the flexible coupling defining, with respect to the engine central axis, a torsional stiffness TS and a lateral stiffness LS such that a ratio of TS/LS is greater than or equal to about 2.0 to reduce loads on the gear system from misalignment of the gear system with respect to the engine central axis.

2. The gas turbine engine as recited in claim 1, wherein the flexible coupling is a fixed flexible support.

3. The gas turbine engine as recited in claim 1, wherein the flexible coupling is a rotatable input shaft.

4. The gas turbine engine as recited in claim 1, wherein the gear system has a gear reduction ratio of greater than or equal to about 2.3.

5. A gas turbine engine comprising:

a fan shaft arranged along an engine central axis;

a frame supporting the fan shaft, the frame defining a frame lateral stiffness FLS;

a gear system rotatably coupled to the fan shaft;

a first flexible coupling and a second flexible coupling at least partially supporting the gear system, the first flexible coupling and the second flexible coupling being subject to at least one type of motion, with respect to the engine central axis, selected from the group consisting of Motion I, Motion II, Motion III, Motion IV and combinations thereof, wherein Motion I is parallel offset guided end motion, Motion II is cantilever beam free end motion and Motion III is angular misalignment no offset motion and Motion IV is axial motion,

the first flexible coupling having a first stiffness defined with respect to the frame lateral stiffness FLS and the type of motion and the second flexible coupling having a second stiffness defined with respect the frame lateral stiffness FLS and the type of motion.

6. The gas turbine engine as recited in claim 5, wherein the first stiffness and the second stiffness are axial stiffnesses with respect to Motion IV.

7. The gas turbine engine as recited in claim 5, wherein the first stiffness and the second stiffness are radial stiffnesses with respect to Motion II.

8. The gas turbine engine as recited in claim 5, wherein the first stiffness and the second stiffness are radial stiffness with respect to Motion I.

9. The gas turbine engine as recited in claim 5, wherein the first stiffness and the second stiffness are torsional stiffness with respect to Motion I.

10. The gas turbine engine as recited in claim 5, wherein the first stiffness and the second stiffness are angular stiffness with respect to Motion III.

11. The gas turbine engine as recited in claim 5, wherein the gear system has a gear reduction ratio of greater than or equal to about 2.3.

12. A gas turbine engine comprising:

a fan shaft arranged along an engine central axis;

a frame supporting the fan shaft, the frame defining a frame lateral stiffness FLS;

a gear system rotatably coupled to the fan shaft; and

a first flexible coupling and a second flexible coupling at least partially supporting the gear system, the first flexible coupling and the second flexible coupling being subject to at least one type of motion, with respect to the engine central axis, selected from the group consisting of Motion I, Motion II, Motion III, Motion IV and combinations thereof, wherein, Motion I is parallel offset guided end motion, Motion II is cantilever beam free end motion and Motion III is angular misalignment no offset motion and Motion IV is axial motion,

the first flexible coupling and the second flexible each having Stiffnesses A, B, C, D and E defined with respect to the frame lateral stiffness FLS, wherein Stiffness A is axial stiffness under Motion IV, Stiffness B is radial stiffness under Motion II, Stiffness C is radial stiffness under Motion I, Stiffness D is torsional stiffness under Motion I, and Stiffness E is angular stiffness under Motion III.

13. The gas turbine engine as recited in claim 12, wherein a ratio of FLS/Stiffness A of first coupling is in a range of about 6.0 to about 25.0, and a ratio of FLS/Stiffness A of second coupling is in a range of about 28.0 to about 200.0.

14. The gas turbine engine as recited in claim 12, wherein a ratio of FLS/Stiffness B of first coupling is in a range of about 10.0 to about 40.0, and a ratio FLS/Stiffness B of second coupling is in a range of about 33.0 to about 1000.0.

15. The gas turbine engine as recited in claim 12, wherein a ratio of FLS/Stiffness C of first coupling is in a range of about 1.5 to about 7.0, and a ratio FLS/Stiffness C of second coupling is in a range of about 16.0 to above 100.0.

16. The gas turbine engine as recited in claim 12, wherein a ratio of FLS/Stiffness D of first coupling is in a range of about 0.25 to about 0.50, and a ratio FLS/Stiffness D of second coupling is in a range of about 2.0 to about 100.0.

17. The gas turbine engine as recited in claim 13, wherein a ratio of FLS/Stiffness E of first coupling is in a range of about 6.0 to about 40.0, and a ratio FLS/Stiffness E of second coupling is in a range of about 4.0 to about 500.0.

18. The gas turbine engine as recited in claim 12, wherein a ratio of FLS/Stiffness A of first coupling is in a range from about 6.0 to about 25.0, a ratio FLS/Stiffness A of second coupling is in a range of about 28.0 to about 200.0, a ratio FLS/Stiffness B of first coupling is in a range of about 10.0 to about 40.0, a ratio FLS/Stiffness B of second coupling is in a range of about 33.0 to about 1000.0, a ratio FLS/Stiffness C of first coupling is in a range of about 1.5 to about 7.0, a ratio FLS/Stiffness C of second coupling is in a range of about 16 to about 100.0, a ratio FLS/Stiffness D of first coupling is in a range of about 0.25 to about 0.50, a ratio FLS/Stiffness D of second coupling is in a range of about 2.0 to about 100.0, a ratio FLS/Stiffness E of first coupling is in a range of about 6.0 to about 40.0, and a ratio FLS/Stiffness E of second coupling is in a range of about 4.0 to about 500.0.

19. The gas turbine engine as recited in claim 12, wherein the gear system has a gear reduction ratio of greater than or equal to about 2.3.